Locking device



1953 MQc. STEBBINS I 2 LOCKING DEVICE Filed June 6, 1961 l2 0 g I p 36 2 f 26 *1 14 2 28 22 k 5 I za 7 0 a 3o f/iz/ FIG- I 48 50 z 36 7e m v2- q 8o 4a 7 Q JV Fla 3 W I INVENTOR. i Ft-16864 MARK C. S'reaamS FIG. 4 BY ATTORNEYS United States 3,873,142 Patented Jan. 15, 1963 3,073,142 LOQKENG DEVICE Mark C. Stebbins, Detroit, Mich, assignor to Mark C. Stebhins and Sons, Inc., Detroit, Mich, a corporation of Michigan Filed June 6, 1961, Ser. No. 115,210 9 Claims. (Cl. 70-92) This invention relates to a locking device for use on a door having a latch operated by a crossbar, or panic bar, as it is referred to in the industry. This type of door latch is used in buildings such as large stores, schools, theaters, and public institutions frequented by the public in relatively large numbers. The panic bar is mounted on the inside of the door so that the door can be opened by merely depressing the bar toward the door. The purpose of this arrangement is to facilitate ready opening of the door and exit from the building under emergency conditions, such as fire, in which people are likely to panic and jam against the exit doors.

It is frequently desirable to discourage traffic out of buildings through little used or remote exits, fire escape doors, and the like. A problem exists on how to accomplish this and still retain the safety feature permitting egress by mere pressure against the panic bar.

The object of this invention is to provide a simple, inexpensive locking structure improved to achieve this result.

Generally the invention contemplates a partial locking device which includes an auxiliary key-operated lock mounted on the door and having a plunger releasably secured by the lock in a position in which it projects toward a stud on the panic bar. The plunger and stud cooperate to secure in place a frangible strut which obstructs doorward movement of the panic bar and prevents operation of the latch. The plunger or stud is tapered to cause the strut to fracture when extraordinary force is applied to the panic bar to facilitate opening the door. When the lock is turned off, the plunger can be depressed against the action of a spring to facilitate shifting the strut out of engagement with the stud on the panic bar to free the panic bar for free latch-operating movements. One form of the invention is shown in the accompanying drawings.

FIG. 1 is a perspective view illustrating a locking device according to this invention installed on a door.

FIG. 2 is an enlarged fragmentary generally sectional view on line 2-2 of FIG. 1.

FIG. 3 is generally a sectional view on line 33 of FIG. 2.

FIG. 4 is a fragmentary sectional view illustrating the locking device in unlocked condition.

Shown in FIG. 1 is a door on which is mounted a conventional latch device 12 which controls movements of a bolt 14 engaged within a keeper 16 mounted on a door jamb 18. The latch mechanism is operated by movements of a lever 20 which supports one end of a panic bar 22, the other end of the panic bar being supported by a lever 26. To open the door, the panic bar is depressed, thereby swinging lever 20 downwardly and toward the door which, through the latch mechanism, withdraws bolt 14 from its keeper. When the panic bar is released, it is swung back upwardly to the FIG. 1 position by conven tional spring means (not shown).

The locking device 28 of this invention includes a keyoperated lock 30 having a threaded barrel 32 secured by a nut 34 to a mounting plate 36 fastened to the front face 38 of door 10 by mounting screws 40 with the operating parts of the lock disposed within a recess 42 in the door. Lock 30 has a revolving plug 42 to which a tailpiece 44 is secured by a screw 46. Extending rearwardly of plate 36 is a body 48 having an opening 50 which slidably supports a plunger 52 having a tapered end portion 54 which projects away from front face 38 of the door toward panic bar 22.

The plunger has a radial shoulder 56 and an adjacent rearwardly extending shank 58 which passes slidably through an opening 60 in body 48. Plunger 52 is urged toward panic bar 22 or to the right, as FIGS. 2 and 4 are viewed, by a compressed spring 62 engaged against shoulder 56 on the plunger and reacting against the base 64 of opening 50. The plunger is retained within opening 50 by a snap ring 66 engaged within a groove in shank 58 and contacting a shoulder 68' on body 48 to the rear of opening 60. Body 48 has an opening 70 into which the rearward end 72 of shank 58 projects.

Tailpiece 44 has an end portion 74 which, in one position of lock 30, projects into opening 70 in alignment with shank end 72 as shown in FIG. 2, the solid-line position of FIG. 3, and the broken-line position of FIG. 4. In the unlocked position, end 74 is rotated out of alignment with the shank to the broken-line position illustrated in FIG. 3. Door 10 is shown as having a reentrant recess 76 for receiving the tailpiece in this position.

Panic bar 22 is provided with a stud 78 projecting toward door 10 and aligned with plunger 52. Stud 78 could be tapered similarly to plunger end 54. A destructible rod or strut 80 is provided for mounting between the panic bar and door by engagement with plunger 52 and stud 78 for the purpose of obstructing doorward movement of the panic bar and consequent withdrawing of bolt 14 to open the door. In the form of the invention illustrated, this strut has the form of a tube diametered so that one end 82 provides a socket which engages around stud 78 and the other end 84 engages against tapered portion 54 of plunger 52.

This strut is made of a relatively rigid, form retaining but frangible material, such as glass or a plastic, which will withstand such forces as are ordinarily applied to panic bar 22 to open the door but which will collapse when extraordinary forces are applied to the panic bar. By way of an example, an extraordinary force which would collapse or destroy strut 80 is a force which a person would exert by pushing vigorously against the panic bar or throwing his weight against it.

In use it may be assumed that initially the parts are in the condition shown in FIGS. 1 and 2. Lock 30 has been installed on the door along with the latch and panic bar, tube 80 has been engaged between stud 78 and plunger 52, and lock 30 has been operated by a key K to turn tailpiece 44 so that its end 74 is aligned with shank end 72. The tailpiece thus secures plunger 52 against being depressed and thereby secures tube 80 in the position shown to obstruct doorward movement of panic bar 22 under any ordinary forces applied thereto. This prevents operation of latch mechanism 12 so that bolt 14 is retained within keeper 16.

When a person pushes on the panic bar in an attempt to open the door, he discovers that the bar will not move and that the door will not open. It has been found in actual use that in nearly every case the person assumes that the door is locked and cannot be opened, and the person finds another exit with an unlocked door through which to leave the building. Even if the person recognizes that it is the tube which obstructs movement of the panic bar, he cannot remove it because it is locked in place and in nearly every case rather than adopt the obviously forbidden course of destroying the tube or breaking out, he will be discouraged and find another door which is unlocked.

To unlock the door in normal use, lock 30 is operated by key K to turn tailpiece 44 to the dotted-line position of FIG. 3 wherein its end 74 is removed from alignment with the end 72 of shank 58 so that plunger 52 can be depressed into recess 50 against the action'of spring 62.

Tube 80 may then be grasped manually and pushed toward the door to depress plunger 52; to the dotted-line position of FIG. 2 thereby disengaging tube end 84 from stud 78 to permit removal of the tube and free panic bar 22 for swinging movements for operating latch mechanism 1-2. To again lock the door, tube is installed between plunger 52 and stud 78 by'the reverse procedure, and lock 39 is operated to turn tailpiece end 74 into alignment with shank end 72.

In the event of an emergency necessitating that door It be opened immediately and there is no time to get a key for operating lock 30, the door can be opened merely by pushing vigorously on panic bar 12. Under this condition, tapered end 54 of plunger 52 will wedgingly expand tube end 84 until it shatters, thereby freeing the panic bar for movement so that the door can be opened. Tube 84) can also be destroyed by striking it a sharp blow with a relatively small tool or even with the heel of the hand or a first. However, it is important that the tube be destructible by force applied directly to the panic bar, since people in panic conditions may not have presence of mind to do anything but push on the panic bar.

The invention provides a partial lock which discourages use of a door but which will yield to pressure on the panic bar when it is necessary to open the door under extraordinary conditions.

Tubes 80 are very inexpensive'items; and after one has been destroyed in an emergency opening of door it), the locking device of this invention is restored to usefulness merely by supplying a new tube.

I claim:

1. In combination with a door latch operated-by a crossbar depressible toward the door on which the latch is mounted, a locking device for the door comprising, a lock adaptedto be mounted on a door adjacent said latch and having a plunger releasably secured by said lock in a position in which it extends awaytfrom the door toward said crossbar, a stud on said crossbar, means forming a strut releasably secured in movement-obstructive .relation to said crossbar byengagementwith said plunger and stud, said strut being destructible responsive to extraordinary force applied thereto to facilitate latch operation independently of the condition of said lock, spring means yieldably urging said plunger into engagement with said strut when said plunger is released by said lock, said plunger being depressible in a direction awayfrorn said crossbar against the action of said spring means when said lock is released to facilitate shifting of said strut out of engagement with said stud for unlocking the door.

2. In combination with a door latch operated by a crossbar depressible toward the door on which the latch is mounted, a locking device for the door comprising, a lock adapted to be mounted on a door adjacent said latch and having a plunger releasably secured by said lock in a position in which it extends away from the door toward said crossbar. a stud on said crossbar, means forming a frangible strut releasably secured in movement-obstructive relation to said crossbar by engagement with said plunger and said stud, one of the parts defined as said stud and said plunger at the portion of its engagement with said strut being contoured so that upon application of extraordinary force to said crossbar, said contoured portion destroys contiguous portions of said strut to facilitate latch operation independently of the condition of said lock.

3. In combination with a door latch operated by a crossbar depressible toward the door on which the latch is mounted, a locking device for the door comprising, a lock adapted-to be mounted on a door adjacent said latch and having a plunger releasably securedby said lock in a position in which it extends away from the door toward said crossbar, a stud on said crossbar, means forming a frangible strut releasably secured inmovement-obstructiverelation to said crossbar by engagement with said plunger and said stud, one of the parts defined asisaid stud and said plunger being tapered at its portion of engagement with said strut and the portion of said strut which engages said tapered portion being tubular so that upon application of extraordinary force to said crossbar, said tapered portion destroys the contiguous tubular portion of said strut to facilitate latch operation independently of the condition of said lock.

4. In combination with a door latch operated by a crossbar depressible toward the door on which the latch is mounted, a locking device for the door comprising, a lock adapted to be mounted on a door adjacent said latch and having a tapered plunger releasably secured by said lock in a position in which it extends away from the door toward said crossbar, said plunger being yieldably springurged toward said position when said lock is released, a stud on said cross bar, means forming a frangible strut having a tubular end portion releasably secured in engagement with said tapered portion'of said plunger and having another end portion detachably secured by said plunger in engagement with said stud, said strut being secured by said plunger and said stud in movementobstructive relation to said crossbar, said one tubular end of said stud being destructible by said tapered portion of said plunger responsive to application to said crossbar of extraordinary force to facilitate latch operation independently of the condition of said lock, said plunger when said lock is released being shiftable against said springurging out of engagement with said stud to free said crossbar for latch-operating movement.

5. In combination with a door latch operated by a crossbar depressible toward the door on which the latch is mounted, a locking device for the door comprising, a key-operated lock adapted to be mounted on a door adjacent said latch and having a movable plunger which extends in a direction toward said crossbar, said lock having a revolving plug with a tailpiece movable responsive to operation of said lock to and from a position in which said tailpiece obstructs depressing of said plunger in a direction away from said crossbar, spring means yieldably urging said plunger toward said position thereof, a stud on said crossbar, means forming a strut releasably secured in movement-obstructive relation to said crossbar by engagement with said plunger and stud, said strut being destructible responsive to extraordinary force applied thereto to facilitate latch operation independently of the condition of said lock, said plunger when released from the obstruction of said tailpiece being depressible against said spring means to facilitate shifting of said strut away from and out of engagement with said stud to free said crossbar for latch-operating movement.

6. In combination with a door latch operated by a crossbar depressible toward the door on which the latch is mounted, a partial locking device for the door comprising, means providing a first support disposed on the door at a location generally aligned with the crossbar, means providing a second support on said crossbar generally aligned with said first support, means providing a strut releasably secured to said first and second supports and extending between said crossbar and door for obstructing doo-rward movement of said crossbar, said strut being destructible responsive to extraordinary force applied thereto to facilitate operation of said latch Without removing said strut from engagement with said first and second supports.

7. In combination with a door latch operated by crossbar depressible toward the door on which the latch is mounted, a partial locking device for the door comprislng,

"a first support on said door and a second support on said crossbar,

a strut eXtending between said supports in movementobstructive relation to said crossbar,

one of said supports including a movable element secured in strut-supporting relation by a releasable lock,

said strut being destructible responsive to extraordinary force applied thereto to facilitate latch operation independently of the condition of said lock, said element being movable to strut releasing position responsive to release of said lock, I said strut being detachable from one of said supports responsive to strut releasing movement of said element to free said crossbar for operation of said latch. 8. The combination defined in claim 7 wherein said first support includes said movable element, said releasing movement of said element being in a direction away from said crossbar.

9. The combination defined in claim 8 wherein said strut and second support include interengaged stud and socket means which are detachable responsive to movement of said strut away from said crossbar upon release movement of said element.

Cone May 11, 1915 Spradling Aug. 27, 1940 

2. IN COMBINATION WITH A DOOR LATCH OPERATED BY A CROSSBAR DEPRESSIBLE TOWARD THE DOOR ON WHICH THE LATCH IS MOUNTED, A LOCKING DEVICE FOR THE DOOR COMPRISING, A LOCK ADAPTED TO BE MOUNTED ON A DOOR ADJACENT SAID LATCH AND HAVING A PLUNGER RELEASABLY SECURED BY SAID LOCK IN A POSITION IN WHICH IT EXTENDS AWAY FROM THE DOOR TOWARD SAID CROSSBAR, A STUD ON SAID CROSSBAR, MEANS FORMING A FRANGIBLE STRUT RELEASABLY SECURED IN MOVEMENT-OBSTRUCTIVE RELATION TO SAID CROSSBAR BY ENGAGEMENT WITH SAID PLUNGER AND SAID STUD, ONE OF THE PARTS DEFINED AS SAID STUD AND SAID PLUNGER AT THE PORTION OF ITS ENGAGEMENT WITH SAID STRUT BEING CONTOURED SO THAT UPON APPLICATION OF EXTRAORDINARY FORCE TO SAID CROSSBAR, SAID CONTOURED PORTION DESTROYS CONTIGUOUS PORTIONS OF SAID STRUT TO FACILITATE LATCH OPERATION INDEPENDENTLY OF THE CONDITION OF SAID LOCK. 